Pick-and-place devices are of importance in automated product handling lines. This is because when combined with sensors such as weighing cells, photocells, cameras and the like, articles on a conveyor belt can for example be identified according to size, colour, shape etc. and picked-up and placed for example on an another conveyor, or into preformed packaging. Also, in the electronic manufacturing process, electronics components are being transferred from one station to another station for further processing. The pick-and-place operation generally requires vacuum to pick-up a work-piece and unloads it by either purging air or releasing vacuum pressure.
Generally, such pick-and-place apparatus produce rapid transfer operations, during pick-and-place operation, the force exerted on the components are unknown and damage to the components could happen if calibration is not done properly. It is the objective of the present invention to provide a force measuring capability by a feedback control system to set the force within desired range in order to prevent damage on the components or to apply a regulated force during pick-up and placement operation.
During the pick-and-place transfer operation, some applications desire to detect the presence of the work-piece rather than measuring the contact force. The present invention could also make use of the force measuring capability to detect the presence of the work-piece.
US Patent Publication No. 20150147141 discloses a pick-and-place head for transporting a plurality of work-pieces from at least one first location to at least one second location, the pick-and-place head comprising: a plurality of nozzles with each nozzle configured to engage one of the plurality of work-pieces; at least one independent vacuum supply configured to attach to one nozzle of the plurality of nozzles; and, at least one shared vacuum supply configured to attach to at least two nozzles of the plurality of nozzles not attached to the at least one independent vacuum supply. The pick-and-place head further comprising a vacuum sensors configured to indicate whether or not a sufficient force is being applied to the plurality of work-pieces. The pick-and-place head does not provide a force measuring capability that can be used by a feedback control system.